This invention pertains to the art of windshield wipers and more particularly to heated windshield wiper arrangements.
The invention is particularly applicable to a heated windshield wiper arrangement for use on conventional vehicle windshields and will be described with particular reference thereto. However, it will be appreciated that the concepts of the present invention may be advantageously utilized in other environments where it is desired to wipe or otherwise clean a surface.
Heated windshield wipers as a broad general concept are known in the art and many prior designs have been patented and/or placed into use. Some prior designs have included the idea of embedding the heating element directly in the resilient wiper blade while others have focused on mounting some type of heating element to a backing member or to some other area of the overall wiper assembly. Still other prior arrangements have employed heating elements spaced closely adjacent the wiper blade for directly contacting the windshield surface. All of these prior designs and constructions have had certain inherent structural and operational deficiencies which have detracted from their overall efficiency in performing the desired wiping function.
Some of these difficulties have arisen from the complexity of prior designs which rendered them somewhat unreliable over a long period of time and which further rendered them difficult to maintain or repair.
Prior designs having the heating elements disposed directly in the wiper blade often made them cost prohibitive and lead to deterioration of the blade which detracted from their appeal in the general marketplace. Moreover, prior designs and constructions which had the heating element mounted in either the flexible wiper blade or to a blade backing member were such that the overall stiffness of the blade or backing member was increased to a point where it adversely affected resultant wipe quality. Simply increasing the wiper arm pressure increased the load per unit length on the wiper blade which caused it to fold excessively as the blade moved across the windshield. Here too, wipe quality was compromised.
Heretofore, prior windshield wiper assembly designs were such that it was not possible to effectively design around or compensate for the aforementioned stiffness problem. Moreover, the heating elements themselves were subjected to compression and/or tension stresses each time the wiper assembly was bent in the ordinary course of operation to conform to the windshield contour. These stresses oftentimes led to heating element failure requiring premature replacement of the entire wiper blade arrangement. Still further, many prior designs did not provide for protecting the associated heating elements such that they were exposed and subject to attack by natural and other corrosive elements. This too led to premature failure.
In view of the above noted problems with prior art heated windshield wiper designs, it has been found desirable to develop a new and improved arrangement which would overcome such problems and be more practical and acceptable for widespread use. The concepts of the subject invention are deemed to meet these needs and provide a new and improved heated windshield wiper arrangement which is simple in design, economical to manufacture, reliable, allows the blade assembly backing member to have the desired stiffness for achieving good wiping quality, does not stress the heating element and readily adapted to a number of different wiping applications.